Skoda Workshop Service and Repair Manuals

Piston and conrod - Summary of components

t	The following conrod versions are fitted:

t	Conrods with fit pin Pos.6, use here conrod bolts without centering.

t	Conrods without fit pin, use here conrod bolts with centering.

1 -	Piston rings

q	Offset joint 120°

q	use piston ring pliers for removing and installing

q	Marking „TOP“ faces up

q	Inspect gap clearance → Fig.

q	Inspect end clearance → Fig.

2 -

Piston

q	with combustion chamber

q	mark installation position and matching cylinder

q	Installation position and assignment of piston and cylinder → Fig.

q	arrow on piston crown faces towards the belt pulley side

q	use piston ring tensioning strap for installing

q	replace piston if there is any sign of crack formation on the piston body

q	inspect piston projection at TDC → Chapter

q	Ø Piston: 79.47 mm

3 -	Piston pin

q	if stiff, heat piston to 60°C

q	use drift -VW 222 A- for removing and installing

4 -

Circlip

5 -

Conrod

q	pay attention to different version

q	replace as a set only

q	mark assignment to cylinder, refer to -A-

q	Fitting location: Markings -B- must be positioned one above the other and point to the belt pulley side

q	axial clearance

Wear limit: 0.37 mm

6 -

Fit pin

q	the fit pins must fit tightly in the conrod, not in the cap

7 -	Bearing shell

q	Check fitting position

q	do not mix up used bearing shells (mark)

q	ensure tightly located in retaining lugs

8 -	Cylinder block

q	inspect cylinder bore → Fig.

q	Ø Cylinder: 79.51 mm

9 -	Conrod bearing cap

q	Check fitting position

10 -	Oil injection nozzle

q	for piston cooling

11 -

25 Nm

q	replace without sealant

12 -	Conrod bolt, 30 Nm + torque a further + 90° (1/4 turn)

q

replace

q	Oil thread and contact surface

Inspecting piston ring gap clearance Special tools and workshop equipment required t  Feeler gauges Test sequence –  Push in ring at right angles to the cylinder wall from the top through to the bottom cylinder opening, about 15 mm from the cylinder edge. To insert use piston without rings.

Piston ring	New (mm)	Wear limit (mm)
1. Compression ring	0.20 to 0.40	1,0
2. Compression ring	0.20 to 0.40	1,0
Oil scraper ring	0.25 to 0.50	1,0

Inspect piston ring end clearance Special tools and workshop equipment required t  Feeler gauges –  Clean the annular groove before inspecting.

Piston ring	New (mm)	Wear limit (mm)
1. Compression ring	0.06 to 0.09	0,25
2. Compression ring	0.05 to 0.08	0,25
Oil scraper ring	0.03 to 0.06	0,15

Inspecting cylinder bore Special tools and workshop equipment required t  Internal precision measuring instrument 50 to 100 mm Test sequence –  Measure at 3 points crosswise in a transverse direction -A- and lengthwise -B-.    Deviations from specified dimension: max. 0.10 mm   Note Do not measure the cylinder bore if the cylinder block is fixed to the assembly stand with the engine mount -MP1-202-, as this may result in incorrect measurements.

Installation position of piston and assignment of piston/cylinder Special tools and workshop equipment required t  E.g. electric stylus Work procedure –  Mark installation position and assignment on inside of piston (not on piston crown), e.g. with an electric stylus. Pistons in cylinders 1 and 2: Large recess for inlet valve to flywheel side -arrows-. Pistons in cylinders 3 and 4: Large recess for inlet valve to belt pulley side -arrows-.   Note t  For new pistons the cylinder assignment is colour-coded on the piston crown. t  Piston of cylinder 1 and 2: Marking 1/2 t  Piston of cylinder 3 and 4: Marking 3/4